Một người đi xe máy từ A về B với vận tốc là 20km/h và ngược trở lại từ B về A với vận tốc 12km/h . Tính vận tốc trung bình cả 2 đoạn đường đi về của người đó. giải bằng vl8 ạ ! Giúp em với ạ

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